Character presentation device for phototypographical apparatus



April 7, 1970 w. o. GRUBE ETAL 3,504,600 I CHARACTER PRESENTATION DEVICE FORPHQTQTYPOGRAPHICAL APPARATUS Filed July 5. 1967 i 3 Sheets-Sheet 1 INVENTORS WOLFGANG O. GRUBE EL '8. HA RlS NLLOREEY April 7,1970 w. o. GRUBE ETAL 3,504,600

CHARACTER PRESENTATION DEVICE FOR PHOTOTYPOGRAPHICAL APPARATUS- Filed July 5 1967 C I 3 Sheets-Sheet 2 I I U n l y L I w Will J is w M \9 23 -22 26 25 f// h l 24 Ni I 27 33 I 2! 34 .72 r v C L 1L AIL JHL I rum/W (I! INVENTORS WOLFGANG 0. GRUBE URI Z.:ESCOLI "AT-TO NEY CHARACTER PRESENTATION DEVICE FOR PHOTOTYPOGRAPHICAL APPARATUS Wolfgang 0. Grube, Leonia, N.J., and Uri Z. Escoli, New

York, and Joel S. Harris, Valley Stream, N.Y., assignors to Eltra Corporation, a corporation of New York Filed July 3, 1967, Ser. No. 650,841 Int. Cl. B41b 13/08 U.S. Cl. 954.5 6 Claims ABSTRACT OF THE DISCLOSURE A device, for use in photocomposing machines, which corrects misalignment of characters projected from a character matrix through an optical projection system onto an output film plane. A pair of optical lenses are mounted in front of the output film plane, one of which is moved vertically by the motion of connected integrating linkages so as to cause a corrective-vertical shift in the optical path of character rays passing through the lens, while the other is similarly moved horizontally to effect a horizontal correction.

BACKGROUND OF THE INVENTION The invention relates to photocomposing machines and,

in particular, to a device for correcting misalignment of letters on characters projected onto an output film plane.

In a photocomposing machine the character images are precisely located on a font plate or disk and each such image is selectively brought into coincidence with the optical axis of the machine either by movement of the font plate, in the case of a spinning disk or drum, or by action of the optical elements in a machine having a stationary font plate. In either case it is clear that, unless this character image is in exact coincidence with the optical axis, the registration of characters projected onto a film plane will not be precise. Although slight deviations in the lateral spacing of characters in a printed line is scarcely noticeable, a vertical misalignment is readily apparent. It has been found that in most optical projection systems, such as the one described in U.S. Patent 2,942,538, the tolerances required to attain this exactitude are difficult to achieve economically and technically. In practice this means that a machine which is economically feasible does not produce copy that is'typographically acceptable.

Therefore it is the object of the invention to provide an apparatus which will enable slight misalignments in character placement to be readily and simply compensated for.

While the invention has been found suitable for a character presentation scheme as disclosed and claimed in U.S. Patent 2,942,538, it can also be used in a machine employing a spinning disk, in which case compensation can be made for inaccurate positioning of the character images on the disk.

SUMMARY The object of the present invention is to correct the character misalignment caused by normal tolerances in the types of optical projection systems described above. In carrying out the invention there is provided a pair of moveable lenses which are introduced between the optical projection system and the output film plane. There is also provided means of moving these lenses singly or in unison thereby causing a vertical and/or a horizontal shift of the character rays passing through them. The lenses can be made to assume a determinable unique position for each projected character so that, if an error is introduced in a characters optical path as it is projected through the optical projection system, the correction lenses will shift 3,504,600 Patented Apr. 7, 1970 BRIEF DESCRIPTION OF THE DRAWINGS The foregoign, and other objects, features and advantages of the invention, will be apparent from the following, more particular, description of a preferred embodiment of the invention as illustrated in the accompanying drawings.

FIG. I is a schematic representation of a character projection system for a phototypographical machine employing the present invention;

FIG. 2 is a front elevational view of the mechanism showing the relative position of the vertical lens housing to its associated solenoid integrating linkage assembly;

FIG. 3 is a rear elevational view showing the relative position of the horizontal lens housing to its associated solenoid integrating linkage assembly;

FIG. 4 is a top plan view of the horizontal-integrating linkage assembly;

FIG. 5 is an enlarged detail view of three interconnecting links;

FIG. 6 is a sectional view taken along line 6-6 of FIG. 5; and

FIG. 7 is a simplified block diagram of the circuitry employed to introduce a correction to the correction lens housing.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 schematically represents a character presentation scheme for a phototypographical apparatus such as that described in U.S. Patent 2,942,538. It comprises a light source 11, condenser lens 12, character matrix 13, collimator lens 14, character selection optical wedges 15, and film plane 17. Condenser lens 12 distributes light from source 11 evenly across the face of matrix 13. The rays of light which pass through each individual character emerge from collimator lens 14 as parallel light bundles. The wedges consist of opposed pairs having different face angles, as between pairs, and can be positioned and/or rotated so as to optically scan the matrix and sequentially select desired characters by deviating one of the light bundles emerging from the collimator lens onto the optical axis of the system. Although only two pair of wedges are shown in FIG. 1, it is to be understood that a plurality of such pairs are required for full matrix scanning capability. After the desired character light bundle is projected through the wedges, it is passed through aperture mask 16 (which blocks all other light bundles) and falls on film plane 17 in conjunction with the opening of a shutter (not shown). Due to the number of optical wedges used in a system capable of selecting from a large array of characters, the acceptable tolerances in the specified refraction angle of each wedge cumulatively may be sufiicient to cause a shift of the projected character from the desired optical path.

Moreover, since the wedges are used in varying combinations to select the different characters, the cumulative tolerance errors will differ for the various characters. [I

It is clear that if a light ray passing through a lens strikes a film at a point displaced from the desired point of imaging, the image of the light ray can be brought into coincidence with the desired point by shifting the lens in the appropriate direction a distance equal to the original displacement. Accordingly, since the misalignment of a character image can be compensated for by a pair of correction lenses (shown'dotted on FIG. 1), one lens will be shiftable in a horizontal direction to correct any horizontal misalignment of a character image, and a second lens will be shiftable in a vertical direction to correct any vertical misalignment of the image. Of course, each lens will have-to be capable. of being shifted to any one of a plurality of positions in order to correct for varying degrees of misalignment.

The correction required for each character (and hence the unique position the correction lenses must assume for each'character) can be pre-determined by calibrating each photocomposing machine against a standard character matrix. Each character is projected through the optical projection system and. the misalignment, ifany, is noted. The appropriate correction factor for each matrix is programmed into the machine so as to cause the correction lenses to be appropriately positioned for a character so that when the character image is projected to the film it will have passed through the correction lenses which had previously been positioned to elfect the desired correction for that character. In other words, when a character signal is read to project a character, the signal will also be used to shift the correction lenses to provide the desired correction as determined by the calibration procedure.

The present invention accomplishes this programming by causing a solenoid operated linkage to produce an output in response to an input energizing signal associated with the selection of a specific character for projection. The linkage output is connected to the correction lens housing and produces a proportional movement in that member such that the lens is properly positioned to correct the selected characters optical path.

FIG. 2 shows the vertical correction lens holder 18 mounted to support 19 by flexible bands 20 and 21. Lens 22 is set within the holder and an arm 23, attached to the holder by screws 24, is seated in the output link 25 of the vertical solenoid-integrating link assembly 26. Arm 23 is moved vertically in response to an additive movement of the solenoid-driven linkage. The maximum vertical displacement of the lens is .0375 inch (a two unit shift of a character on the film plane) achieved when all solenoids are energized. Spring 27 returns the lens holder to its normal rest position upon the deenergizing of the solenoids and the relaxation of the output linkage.

FIG. 3 shows the horizontal correction lens holder 28 mounted to support 29 by flexible bands 30 and 31. Lens 32 is set within the holder and arm 33 is seated in the output link 34 of horizontal solenoid integrating link assembly 35. Arm 33 is moved horizontally in response to an additive movement of the solenoid driven linkage, hereinafter to be described. The maximum horizontal displacement is .0475 inch. Spring 36 returns the lens holder to its normal rest position after the solenoids are deenergized. The normal rest position of both lenses causes a maximum vertical or horizontal shift in the optical path of a projected character. In practice, therefore, each lens will usually be made to assume some intermediate position for each presented character requiring correction.

FIG. 4 shows the component parts of the horizontal solenoid integrating linkage assembly. The operation of this assembly will be described in detail and will serve as a description of the vertical assembly since both operate in the's ame manner.

"The drawing shows four solenoids connected by an integrating linkage system. A point on output link 34 imparts motion to the attached arm of the horizontal lens holder proportional to the number of solenoids energized. The four solenoids are adjusted so that, when energized, each presents a different lens displacement. In addi- -tion, 'due to the additive qualities of the linkage, the Solenoids maybe energized in any combination displacing the horizontal lens proportionately.

Referring to FIG. 4, solenoids 37 and 38 are connected to link 39 by pins 40' and 41 respectively. Link 39 is connected. to link 42 by screw 43. Solenoids 44 and 45 are connected in a similar manner to link 46 by pins 47 and 48; link 46 is connected to link 49 by screw 50. Output link 34 is connected to link 42 by screw 51 and to link 49 by screw 52.

To illustrate the relationship of each link to the others, assume that a projected character requires a .0025 inch horizontal correction. This correction requires that solenoid 37 be energized causing links 39 and 42 and output link 54 to cooperate to move point 0 on the output link the required correction distance. Point 0 seats output arm 33 of the horizontal lens housing and the movement of point 0 is transferred directly to the arm. FIG. '5 shows the relationship of these three links to each other. When solenoid 37 is energized, it pulls a point at pin 40 .020 inch.to wards the right (away from link 34). Since solenoid 38 has not been energized, pin 41 remains a fixed point and 'becomesthe pivot about which link 39 rotates. Link 42 is connected to the midpoint of link 39 and is moved only /2 the distance pin 40 is moved, or .010 inch. Link 34, connected to link 42 at screw 51, is forced to pivot about screw 52. Screw 51 is located a distance of 4x from screw 52, i.e., /s of the distance to point 0. Point 0 is a distance x from the pivot point. Point 0 then moves in the opposite direction of screw 51 movement and at A of its distance, i.e., .010/ 4 or .0025 inch, the required correction. It is seen that point 0 can be made to move different increments by connecting the links to different points or changing the location of point 0, or both. In the above example,

if solenoid 38 were also energized, the movement of force would be equally applied at screw 43 and link 42 would be moved the full .020 inch and point 0 would move .005 inch. When solenoids 44 and 45 are energized, the possible positions point 0 can assume increases in the present inven-.

tion, 16 incremental positions (resulting in 16 corrections) are possible. The total displacement of the horizontal lens from one extreme to another is .0475 inch (all solenoids deenergized to all solenoids energized). In other embodiments, the number of incremental positions and the total displacement can be increased by increasing the number of solenoids.

The above discussion described the mathematical relation of the links to each other. The actual mechanical operation must now be considered. As solenoid 37 is energized, it travels a distance .020 inch and pulls link 39 the same distance. Link 39 is forced to pivot simultaneously about pin 41 and about link 42 connection point screw 43. The ability of the links to pivot about each other at their point of connection is due to the manner of their joining. FIG. 6 shows a shoulder screw 51 connecting links 34 and 42. The screws edge projects a short distance below link 42s bottom surface. The small projection permits washer 54 and nut 55 to be brought up flush against screw 51 rather than against the bottom surface of the link thereby permitting a small degree of play to develop between the contacting surfaces of links 34 and 42.

As link 42 is urged to the right, it exerts a force against guide spring 56 at pin 57. Spring 56 is bent around post 58 and is fixed to the post by washer 59 and E-ring 60. Spring adjusting screw 61 is set to provide a desired tension on the spring. Link 42 is forced to travel in a straight horizontal path between pin 62 and eccentric 63. Pin 62 is one-half of a dowel pin with the flat surface facing the link. Eccentric 63 can be turned so as to lean away from or into the links side. This arrangement permits less rigid tolerances to be employed when tooling the link width, i.e., if made too wide, the eccentric can be turned outward to accommodate the link. Broad headed pin 64, shown in dotted form, is mounted beneath tance required for the particular character being projected. After the character image is projected into its corrected position'on the film plane, solenoid 37 is deenergized. The solenoid arm pulls in until its motion is stopped by the collar 65 encountering the solenoid housing. Link 39 is held rigid by the arms of the solenoid while tension is maintained on link 42 in a direction away from link 39 by the still partially tensed spring 56.

The operation of links 39 and 42 is identical to that of links 44 and 45 with the same elements (guide spring, eccentric, etc.) being used.

The positioning of the horizontal and vertical lenses operates under control of the circuits shown in FIG. 7. As previously explained, correction factors for each character were determined before a machine is installed and are introduced so as to cause the lenses to modify the optical path when that character is selected. When the position of an input tape is read by tape reader 66 (or keyboard insertions are made) multi-level binary code voltages which define both the character and its position on a matrix are applied to a binary to decimal decoder. Assuming a specific character has been read, the decoder (consisting of a series of AND gates) will convert the binary code representing a character into a single line output which is then applied to a diode board consisting of as many pairs of diodes as there are input voltages (a typical matrix containing 64 characters will require a diode board having 64 inputs from the decoder and 128 diodes). Each input signal applied to its associated diode pair provides two outputs; one output is sent to the horizontal patchboard 69 and the other to the vertical patchboard 70. These patchboards are wired at the time the character corrections are being determined and consist of mounted wire patches connected to one of 15 decimal output correction terminals. Ideally, a patch is inserted for each character; practically it has been found that characters contiguous to each other on the character matrix (four characters embraced in a square) will require corrections so similar that anaverage correction can be applied. Thus for a matrix containing 256 characters, the two patchboards will each consist of 64 patches, each patch accommodating four character input connection signals. Those character groups requiring the same amount of corrections are interconnected in series by jumpers and one jumper is then used to connect all like points to the appropriate decimal output terminal. The output terminals are numbered from 8 to +7 and include a zero; these numbers represent the amount of correction units necessary to properly align the character and correspond to the number of unique positions the linkage assembly previously discussed can assume. Since the correction factor for each group of characters is determined and set during the calibration of the individual machine, the input signal value is always converted to an output signal of the desired value.

The vertical and horizontal correction outputs from the patchboards are applied to decimal-to-binary encoders 71. These encoders charge the decimal correction signals into binary outputs which are then applied to flip-flop and AND gate circuits 72. The AND gates, when a character is recognized and, when strobed, provide output correction signals to energize that particular combination of solenoids in horizontal or vertical linkage assembly 35 or 26 required to mechanically position the horizontal and vertical lens into the corrective position.

What is claimed is:

1. In a phototypographical apparatus, a character presentation system having a character grid bearing an array of characters thereon, an optical system for projecting images of selected characters onto sensitized material, and means for selecting the characters whose images are to be successively projected, said system including a first movable lens interposed in the optical path of projected character images, a second movable lens interposed in the optical path of projected character images, means for moving said first lens vertically in selectable incremental distances, means for moving said second lens horizontally in selectable incremental distances, and patchboard means having input terminals representing character images to be projected and output terminals representing the incremental movement required of a lens to determine in accordance with the character selected for imaging onto sensitized material the incremental movement of said first and said second lenses for correcting misalignments of projected character images.

2. A character presentation system according to claim 1 wherein each means for moving a lens vertically or horizontally into a selected position includes an integrating linkage whose output link is connected to the associated lens, and means for moving individual links of said linkage singly or in combination so as to cause said output link to assume a plurality of positions incrementally.

3. A character presentation system according to claim 2 wherein said means for moving the links of said linkage includes a plurality of solenoids each of which moves a link a fixed distance, and means for selectively energizing said solenoids, either singly or in combination, to thereby move a lens a predetermined incremental distance.

. 4. A character presentation system according to claim 1 wherein said patchboard means includes a pair of patchboards, one for determining movement of the first lens, and one for determining movement of the second lens.

'5. A character presentation system according to claim 3 wherein said means for selectively energizing said solenoids includes a patchboard having input terminals representing character images to be projected and output terminals representing the incremental movement required of a lens for a particular character image.

6. A character presentation system according to claim 5 including means for converting the value of each output terminal representing a desired incremental movement from a decimal to a binary value in a decimal-to-binary encoder. References Cited UNITED STATES PATENTS 2,930,297 3/ 1960 Moyroud 954.5 3,126,799 3/1964 Stauifer 954.S

JOHN M. HORAN, Primary Examiner L. H. MCCORMICK, 1a., Assistant Examiner 

